Archivist of the United States John W. Carlin was pushed by the White House in December to submit his resignation without being given any reason, Senate Democrats disclosed last week at a hearing to consider President Bush's nomination of his successor.

The Democrats said the White House should explain why it asked Carlin to resign. He said in a letter to Sen. Carl M. Levin (D-Mich.) that White House counsel Alberto R. Gonzales called him Dec. 5 and told him "the administration would like to appoint a new archivist." Carlin said, "I asked why, and there was no reason given."

Critics have suggested Bush may have wanted a new archivist to help keep his or his father's sensitive presidential records under wraps. Under the Presidential Records Act of 1978, many of President George H.W. Bush's papers are due to become public in January.

The 1984 law establishing the National Archives and Records Administration provides that the archivist will serve an indefinite term and can be replaced if he resigns or is removed by the president. If he is removed, "the president shall communicate the reasons for any such removal" to Congress, the law says.

Disclosure of the circumstances surrounding Carlin's decision to step down overshadowed the testimony of Bush's nominee, Allen Weinstein, and could delay any plans to confirm him before the November elections.

Carlin said in his July 22 letter to Levin he would like to remain in his post for four more months so he could complete several initiatives he had undertaken. They include getting congressional funding for development of "a groundbreaking system that will allow the government to manage and preserve any kind of electronic records, now and in the future."

Two weeks after the call from Gonzales, Carlin told the president he would resign -- the Dec. 19 letter contained no hint of what prompted his decision. Democrats on the Senate Governmental Affairs Committee said it amounted to a forced removal, and Bush should be required to give his reasons for it.

Committee Chairwoman Susan Collins (R-Maine) pointed out that Carlin has not quit yet. Appointed by President Bill Clinton in 1995, Carlin wrote Bush that he would submit his formal resignation "upon the confirmation and swearing in" of the next archivist.

The White House had no immediate comment when asked why the president wanted to replace Carlin. White House spokeswoman Erin Healey said only that "Mr. Carlin has submitted a letter stating his intention to resign, and Mr. Bush has a responsibility to appoint someone to fill that position."

Weinstein, a historian and an expert on emerging democracies, won praise for what both Republicans and Democrats called remarkably candid testimony about his determination to open as many government records as possible and his disdain for partisan considerations.

Asked about an executive order restricting release of presidential records that Bush issued in 2001, Weinstein expressed distaste for it as a private citizen. He said it "tilts the balance -- at least temporarily -- in favor of greater confidentiality and less public disclosure." If confirmed, he said he would work to change it but would feel obliged to defend the order against a lawsuit by the American Historical Association seeking to overturn it.

Sen. Richard J. Durbin (D-Ill.) said Weinstein should put the Presidential Records Act first. It envisions disclosure of confidential presidential records 12 years after a president leaves office, but Bush's order establishes new hurdles to access to such records.

Weinstein rejected the notion that he had made a deal to keep the Bushes' papers secret. He said no one at the White House had raised the issue. If anyone had, he said, he would have declined the nomination.

At the same time, Weinstein offered a chronology that reflected an early White House determination to get rid of Carlin. Weinstein said he was invited to meet with Dina Powell, director of presidential personnel, on Sept. 23 to talk about the possibility of his nomination.

In late November and early December, Weinstein said he was asked to fill out White House and FBI investigative forms for the job. Bush announced the nomination April 8.

In an interview earlier this year, Weinstein said that when he was first contacted about the job, he noted he was a Democrat.

Weinstein, a former professor at Boston University, Georgetown University and Smith College, has written several books, notably "Perjury: The Hiss-Chambers Case."